Infant Brain and Behavioral Signatures of Later Emerging Risk for Psychopathology Little is known about the trajectories of brain and behavioral development during infancy that anticipate and predict clinically impairing patterns of functioning observed during the preschool years. The prevalence of psychiatric symptomatology in preschool-aged children, combined with the possibility of common initializing pathophysiological events shared across various disorders, converge to highlight the infant and toddler period as uniquely suited for identifying atypical trajectories of brain and behavioral development that anticipate later emerging psychopathology. Characterizing trajectories that deviate from normative patterns of development during this time period may elucidate causal mechanisms of mental illness, mechanisms that subsequently could be targeted for strategic intervention/prevention. The proposed research will combine state-of-the-art neuroimaging technologies developed by the Human Connectome Project with a developmental approach to the NIMH Research Domain Criteria initiative. Longitudinal brain imaging (sMRI/DWI/fcMRI) and behavioral assessment (selected for relevance to later emerging psychopathology and acquired via direct assessment, parent report, and state-of-the art eye tracking procedures) will be conducted on 4 occasions between 3 and 15 months with a 5th assessment at 24 months of age. Dimensional aspects of clinically relevant behaviors will be characterized during a final 6th assessment between 30 and 36 months of age. The contribution of the proposed research is expected to be a comprehensive characterization of longitudinal brain development in the first years of life, coupled with a longitudinal characterization of behavioral constructs selected for their relevance to later emerging psychopathology. This contribution will be significant because the empirical data acquired will anchor a new paradigm of inquiry into the developmental processes that temporally precede the emergence of clinically impairing patterns of functioning, augmenting future efforts focused on strategic prevention of mental illness. The interdisciplinary synthesis that approaches clinical neuroscience or biological psychiatry from a developmental perspective represents an innovative departure from efforts designed to characterize neural signatures of DSM defined disorders examined years after the incipient pathophysiological events. More specifically, mapping trajectories of neural circuit development to behavioral constructs specifically selected for their relevance to later emerging psychopathology (Elison et al., 2013a; Elison et al., 2013b) highlights a novel developmental approach to the RDoC initiative. Indeed, these mappings will be characterized prior to the manifestation of clinically impairing patterns of functioning, and will be used to predict later emerging clinically relevant behaviors. Characterizing developmental signatures of later emerging psychopathology has the potential to alter the landscape of early identification and early intervention/prevention of psychiatric and neurodevelopmental disorders.